Network Routing and Switching Assessment 2022

COIT20261 Network Routing and Switching Term 2, 2019
Assignment item —Written Assessment-2
ANSWER TEMPLATE ASSIGNMENT TWO
Type your answers in the spaces provided
Marking criteria: Your answers will be marked based on technical correctness,
completeness, clarity, originality and relevance. Proper use of referencing conventions
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expressed in your own words. An answer is unacceptable if it is composed mostly of
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Questions Mark
allocated
Mark
earned
Question 1: (10 marks) 5 each
table
Answer: Routing table of router R1:
Mask Network address Next-hop address Interface
255.255.0.0 150.3.0.0 150.3.0.1 M0
255.255.192
.0
150.32.0.0 150.32.0.1 M1
255.255.255
.0
200.11.60.0 200.11.60.1 M1
255.255.252
.0
140.21.0.0 140.21.0.1 M2
255.255.255
.0
220.10.40.0 150.3.0.3 M0
255.255.192
.0
161.22.0.0 150.3.0.3 M0
Routing table of router R4:
Mask Network address Next-hop address Interface
255.255.0.0 150.3.0.0 150.3.0.1 M0
255.255.192
.0
150.32.0.0 150.32.0.1 M1
255.255.255
.0
220.10.40.0 150.3.0.3 M0
5 max
5 max

COIT20261 Network Routing and Switching Term 2, 2019
Assignment item —Written Assessment-2
255.255.192
.0
161.22.0.0 150.3.0.3 M0
255.255.255
.0
200.11.60.0 200.11.60.1 M1
255.255.252
.0
140.21.0.0 140.21.0.1 M2
Question 2: (5 marks)
a) Classful routing does not support VLSM and CIDR while classless
routing supports both CIDR, VLSM and FLSM. Hello messages are
used with classful routing in which an address is divided into three parts-
network, subnet and host. With classless routing, an address is divided
into two parts only-subnet and host.
1 max
b) Upon receiving a packet destined for 200.11.60.120, R3 checks its
routing table entry in order to determine the best path through which to
forward the packet. R3 has three directly connected routes-
220.10.40.0/24, 161.22.0.0/18 and 150.3.0.0/16. Now that there is no
route matching the destination, the router considers its remotely learnt
routes. This route is found to have been learnt through M0 (150.3.0.2)
through its M0 interface. The packet is then forwarded out of this
interface.
2 max
c) From R3, a packet whose destination address is 150.32.203.10 is
forwarded out through R3’s M0 interface. On this packet, an address
150.3.0.1 is added on the packet. On arriving at R4, it is then de-
encapsulated so that its address can be learnt. Upon finding the
destination address, the packet is further routed out of the network
through the M1 (150.32.0.1) R4’s interface.
2 max
Question 3: (10 marks)
1) TCP congestion control techniques help in the mitigation of congestion
or prevent it from occurring a network. Congestion window (cwnd) and
sliding window (rwnd) are used for this purpose. Rwnd is maintained by
a message recipient and is used in flow control. Cwnd on the other hand
is maintained by the sender for each session and represent the maximum
amount of data that can be sent over a link. Cwnd is initially set to
maximum segment size following successful synchronization between
1 max